As telecommunications usage increases as a result of, for example, increased Internet usage, increased types of communications, and population growth, telecommunications providers are required to provide greater voice- and data-carrying capacity. In order to reduce cost and the amount of time required to provide the increased capacity wavelength division multiplexing (WDM) and dense wavelength division multiplexing (DWDM) have been developed, which provide increased capacity without requiring new fiber optic cables.
WDM and DWDM technologies combine multiple optical signals into a single fiber by transporting different signals on a different optical wavelengths or channels. Interleaving and deinterleaving of optical channels is typically accomplished with thin film optical filters. However, multiple layers of film are required to interleave and deinterleave multiple channels, which increases the cost and complexity of a component. Another disadvantage of multiple layers of thin film for filtering is that the thin films break down over time, especially when operating under high power conditions.
What is needed is an improved optical device for use with WDM and/or DWDM optical signals. Prior attempts to improve optical devices are disclosed in U.S. Pat. No. 4,566,761 issued Jan. 28, 1986 to Carlsen et al; U.S. Pat. No. 4,685,773 issued Aug. 11, 1987 to Carlsen et al; and U.S. Pat. No. 5,694,233 issued Dec. 2, 1997 to Wu et al, which are incorporated herein by reference.